Method for performing out-focus using depth information and camera using the same

Abstract

A camera and a method for extracting depth information by the camera having a first lens and a second lens are provided. The method includes photographing, by the first lens, a first image; photographing, by the second lens, a second image of a same scene; down-sampling the first image to a resolution of the second image if the first image is an image having a higher resolution than a resolution of the second image; correcting the down-sampled first image to match the down-sampled first image to the second image; and extracting the depth information from the corrected down-sampled first image and the second image.

What is claimed is: 
     
       1. A method for performing an out-of-focus effect by a camera having a first lens and a second lens, the method comprising:
 photographing a first image with the first lens and photographing a second image of a same scene with the second lens, a first image resolution of the photographed first image being higher than a second image resolution of the photographed second image; 
 extracting a depth map from the first image and the second image using a stereo matching method; 
 up-sampling the extracted depth map to the first image resolution of the first image; and 
 performing an out-of-focus effect comprising blurring pixel regions of the first image having depths in the depth map that satisfy a predetermined condition using the up-sampled depth map. 
 
     
     
       2. The method as claimed in  claim 1 , wherein the first image has a higher optical magnification than an optical magnification of the second image. 
     
     
       3. The method as claimed in  claim 2 , wherein extracting the depth map further comprises:
 cropping a portion of the second image in order to make an image region acquired in the second image coincide with an image region acquired in the first image; 
 down-sampling the first image to a resolution of the second cropped image; 
 correcting the first down-sampled image to match the second cropped image; and 
 extracting the depth map from the first corrected image and the second cropped image. 
 
     
     
       4. The method as claimed in  claim 1 , wherein the out-of-focus effect is performed using a convolution filter. 
     
     
       5. The method as claimed in  claim 1 , wherein the camera is one of a digital still camera and a phone camera. 
     
     
       6. The method as claimed in  claim 1 , further comprising setting a reference pixel and the predetermined condition comprises depth that is equal to or greater than a depth of the reference pixel. 
     
     
       7. A camera comprising:
 a first lens; 
 a second lens; 
 a first image sensor configured to acquire a first image through the first lens, the first image having a first image resolution; 
 a second image sensor configured to acquire a second image of a same scene through the second lens, the second image having a second image resolution lower than the first image resolution; 
 an image processor configured to extract a depth map based on the acquired first image and the acquired second image using a stereo matching method and up-sample the extracted depth map to the first image resolution of the first image; and 
 a controller configured to perform an out-of-focus effect comprising blurring pixel regions of the first image having depth in the depth map that satisfy a predetermined condition using the up-sampled depth map. 
 
     
     
       8. The camera as claimed in  claim 7 , wherein the first image has a higher magnification than an optical magnification of the second image. 
     
     
       9. The camera as claimed in  claim 8 , wherein the image processor is further configured to crop a portion of the second image in order to make an image region acquired in the second image coincide with an image region acquired in the first image, perform down-sampling of the first image to a resolution of the second cropped image, correct the first down-sampled image to match the second cropped image, and extract the depth map from the first corrected image and the second cropped image. 
     
     
       10. The camera as claimed in  claim 7 , wherein the camera is configured to perform the out-of-focus effect using a convolution filter.